ICON carries four different instruments to explore Earth's upper atmosphere. The MIGHTI instrument, an example of an interferometer, looks at winds and temperatures in the ionosphere. In this video,  Drs. John Harlander and Chris Englert explain what an interferometer is and what MIGHTI will be investigating.

"The atmosphere naturally just glows at those altitudes, more during the day and less during the night...and by just looking at the color of this airglow, we can find out about the wind and the temperature. So the atmosphere... is helping us to understand how it is behaving by sending out this airglow. If we build the right instruments to look at particular aspects of the color of the airglow, we can get information that we want."
—  Dr. Chris Englert, MIGHTI instrument lead

ICON’s Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument includes two identical optical assemblies, one for each of the perpendicular fields of view that will observe thermospheric wind-vector and temperature profiles. An engineering unit of the optical assembly was completed and successfully vibration tested in June 2015 at the Naval Research Laboratory.